Check valves are normally used in material flow control systems to discriminate between directions of flow, i.e., a closure member is held off of a seat by material flow in one direction but is seated by flow of the same or a similar material in the opposite direction. A ball check valve is one well-known example.
Another type of direction-responsive check valve is shown in the U.S. Pat. No. 4,523,610 to Orrico. The Orrico check valve utilizes an elastomeric membrane stretched across a valve chamber normal to the direction of fluid flow. The membrane has a solid, impermeable center but has a circular pattern of relatively large holes formed radially outwardly of the solid center portion. When fluid flows into the valve body in one direction, the large holes in the membrane permit the flow of fluid to flow on through the valve. When fluid flows in the opposite direction, the center section of the membrane is, at least in theory, displaced in the direction of fluid flow stretching the membrane and essentially closing a number of outlet holes in the valve body.
U.S. Pat. No. 3,749,353 to Pauliukonis shows another elastomeric membrane valve in which the normal position of the membrane permits flow parallel to and along one face of the membrane. The application of fluid pressure to the opposite face of the membrane from a pilot or control source flexes the membrane into a second position which impedes or stops material flow. A similar membrane valve with mechanical actuation is shown in U.S. Pat. No. 3,275,291 to Meijers.